Electroplated propeller for aerial vehicles



M. 0. ST. JOHN.

ELECTROPLATED PROPELLER FOR AERIAL VEHICLES.

, APPLICATION FILED FEB. 18, 1920.

1,385,802. Patented July 26, 1921.

:ETIW w WW I v M45; 6. JZ'JOH/V b a m making the same.

UNITED STATES PATENT OFFICE.

MILES 0. ST. Jams, OF CHICAGO, ILLINoIs, ASSIGNOR OF ONEHALF T0 JAMES ERIGKSON, OF CHICAGO, ILLINOIS.

ELECTROPLATED PROPELLER FOR AERIAL VEHICLES.

Specification of Letters Patent.

Patented July 26, 1921.

Application filed February 18, 1920. Serial No. 359,523.

To all whom. it may concern:

Be it known that I, MILES C. ST. JOHN, a citizen of the United States, and a res-ident of the city of Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Electroplated Propellers for Aerial Vehicles;-and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawings, and to the numerals of reference marked thereon, which form a part of this specification.

This invention relates to an electroplated propeller for aerial vehicles and process of Airplane propellers of the type ordinarily used are constructed of wood and on account of the great strength needed the wood which is used in the con struction must be the very best. These wooden propellers are carefully formed and finished by hand and their manufacture is an expensive process. After the wooden propeller is finished and balanced by hand, the problem of protecting the surface thereof from the weather arises. This problem has proven to be'a serious one and heretofore no really satisfactory method has been devised for completely protecting the airplane propeller from the ravages of the weather. Slight imperfections in the varnish causes checking and cracking to set in and when the varnish is damaged moisture is allowed access to the propeller wood and the propeller is soon rendered useless.

It is an object, therefore, of this invention to provide a propeller for aerial vehicles'the surface of which is protected by a coat of metal deposited thereon by an electrolytic process. 1

It is also an object of this invention to provide an electroplated airplane propeller. It is another object of this invention to provide a process of making a propeller for aerial vehicles wherein the propeller is.

formed of wood pulp to the approximate shape desired, a protecting coatof metal deposited on the surface thereof by an electro- .lytic process and balancin of the propeller is formed from pressed fibrous material and protected 'and strengthened by a coat of metal deposited on the surface thereof by an electrolytic process.

Other and further important objects of this invention will be apparent from the disclosures in the specification and the accompanying drawings.

The invention (in a preferred form) is illustrated-in the drawingsand hereinafter more fully described.

On the drawings:

Figure 1 is a View in front elevation of an electroplated propeller for aerial vehicles embodying the principles of this invention.

Fig. 2 is a section on line 2-2 of Fig. 1, showing the interior or body of the propeller constructed of pressed fibrous material.

Fig. 3 is a section on line 3-3 of Fig. 1 showing the pressed fiber construction.

As shown on the drawings: i

The propeller of this invention comprises in general the blade portions 1 and the hub 2, both of which portions are covered by a coating of electrolytically deposited metal 3. Said coating 3 is preferably formed from some non-corrosive metal such as copper,

' bago to the surface thereof.

Themetal to be deposited and the prepared propeller are next deposited in a solution of electrolyte, as, for example, copper sulfate. In this electrolytic process the metal constitutes the positive electrode and the prepared graphited propeller constitutes the negative electrode. Said electrodes are connected together by a conductor of electri'city and asource of direct current such as a storage battery or electrical machine is connected in the circuit. Due to the wellknown process of electrolysis, the copper from the positive metal electrode will be deposited on the graphited propeller or the negative electrode. This process of deposltion of metal will cover the surface of the propeller far more thoroughly than would be -possible by the use of varnish apphed either by dipping or by manual means. The surface of the propeller is covered so thoroughly that neither air nor moisture can gain access thereto. The metallic covering 3 may be built up to any thickness desired by said process of electrolytic deposition and thus may be used to add strengthand rigidity to the propeller. This fact makes pos iible the forming of the interior-portion 0 the propeller from pressed fibrous material suchas wood pulp, a feature which is particularly important due to the increasing scarcity of suitable timber for airplane propellers. The edgesof the propeller blades '1 may also be built out to any form desired by this process of electrolytic deposition, and if such edgesare subsewith one metal and to build out the tips of.

the blades with another metal.

As'may be clearly seen from the foregoing description, this invention provides an ef fective method of protecting airplane'propellers from the weather. In addition, the

"metal covering provided adds rigidity to the propeller and makes possible the con-' struction from stamped fibrous material, heretofore described.

Balancing of the propeller and building up of the edges and tips of the-blades is much,

more effectually and economically accom-' plished than heretofore possible.

i electrolytically depositing metal. This con-,

The process of this invention provides an economically constructed propeller for aerial vehicles the life of which is Practically in definite. Damagedpropellers can be easily repaired and rebalanced by the process of stitutes a great superiority over the old type of wooden propellers where slight damage is irreparable and the damaged propeller must be replaced by a new one.

I am aware thatnumerous details of conv struction may be varied through a wide range without departing from the principles of this invention, and I therefore do not purpose limiting the patent granted otherwise than necessitated by the prior art.

I- claim as my invention: 1. A propeller comprlsing a core of pressed .fibrous pulp, and an electroplating of metal.

2. A propeller comprising a core of pressed fibrous pulp, an electroplating of metal and at the required points an additional electroplating of metal.

3. The process of making a propeller which consists in pressing a fibrous pulp to the form of a core, coating said core with a substance capable of receiving an electrodeposit of metal, electroplating said coated core with metal and balancing the propeller by electrodepositing additional metal at the requisite points. i

v 4. The process of making a propeller 'which consists in pressing a fibrous pulp to the form of a core, electroplating said core with metal and balancing: the propeller by electrodepositing additional 'metal at the requisite points. 1

5. The process of making a propeller the form of a core, electroplating said core with metal and balancing the Propeller by electrodepositing additional metal at the requisite points, different kinds of metal being used for coating different parts of said propeller. v

6. The process of making a propeller which consists in pressing a fibrous pulp to the form of a cor electroplating said core with metal, different .kinds of metal being used for coating different parts of. said pro peller.

In testimony whereof I have hereunto subscribed my name in the presence of two subscribing witnesses. 4

' MILES 0. ST. JOHN.

. Witnesses 5 RIDSDALE ELLIS, CARLTON HILL.

which consists in pressing a fibrous pulp to] 

